Dark Flow is a hypothetical phenomenon in which galaxy clusters are observed to be moving in a uniform direction across the universe. This movement is in addition to the expected expansion of the universe, and suggests the presence of an external force pulling on these clusters.
Dark Flow is currently considered to be a theory, as it has not been definitively proven or observed. However, there is evidence from observations made by the Planck telescope that support the existence of this phenomenon.
The exact cause of Dark Flow is still unknown and is a subject of ongoing research. Some theories suggest that it could be caused by gravitational interactions with matter outside of our observable universe, while others propose exotic particles or modifications to the laws of physics.
Dark Flow and Dark Matter are two separate concepts. Dark Flow refers to the observed movement of galaxy clusters, while Dark Matter refers to the invisible matter that scientists believe makes up a significant portion of the total mass in the universe.
If Dark Flow is proven to exist, it would challenge our current understanding of the universe and the laws of physics. It could also provide new insights into the nature of dark matter and the structure of the universe on a larger scale.